Capturing http requests from msiexec using fiddler

Question

How would I capture with fiddler requests made during installation under an msi package?

I have an app that makes several http requests during its installation, through overriding the install method in a windows msi package.

I'd like to be able to capture these requests using fiddler, but cannot. MS Network Monitor 3.4 captures the requests though, so I know the activity is occurring.

I can start fiddler and capture the requests made in a browser, so fiddler itself is working, and I haven't set it, or my installer, to use any non-standard port.

I am simply creating a request and trying to get the response, for now:

var httpRequest = (HttpWebRequest)WebRequest.Create(url);
        try
        {
            using (var httpResponse = (HttpWebResponse)httpRequest.GetResponse())
            {
                using (var responseStream = httpResponse.GetResponseStream())
                {
                    if (responseStream != null)
                        responseStream.Close();
                }

I've done some research, and concluded that fiddler should be able to capture this, so I am not sure what I am doing wrong. Any advice would be most appreciated, thanks.

Update: I've taken the code that I was using in the installer method, and put it in a standalone console app. Fiddler captures the request in that scenario. So what I am seeing, is that the installer cloaks the request somehow, so fiddler does not see it.

Michael Urman Michael Urman · Accepted Answer · 2012-07-27T11:42:27

I haven't worked with Fiddler, so I don't know how you tell it what to watch, but most custom actions execute in a different process than the original msiexec process. Non-impersonated actions often execute in a completely different context (typically an administrative user).

Capturing http requests from msiexec using fiddler

1 Answers